The invention relates to a selective switch, particularly to a selective switch with a sliding member slidable on a printed circuit board for selective control of the switch.
Referring to FIG. 1, a conventional rotary selective switch includes a plurality of hubs 10 each of which is provided with a conductive reed fixed thereon, a plurality of partitions 20 with contacts, two opposing support rods 40 and 41 securely connecting the partitions 20, a rotary knob 30, a rotating shaft 301 rotatable synchronously with the hubs 10 so that the conductive reeds secured on the hubs 10 contact selectively the contacts of partitions 20, and a positioning device including a positioning plate 302 with a plurality of circumferential slots and a steel ball 303 received detachably in one of the slots. As illustrated, a plurality of electric cords are necessary for connecting connectors to the contacts of the partitions 20. The prior art is difficult to weld and thus easy to make a mistake in assembling. When increase in the number of contacts is desired, the number of the partitions 20 and the length of the rotating shaft 301 must be increased. Then, the torsion of the rotating shaft 301 results in a certain shock at the end portion of the rotating shaft 301 so that the reeds can not easily register the contacts at the end portion of the rotating shaft when rotating. In addition to the poor contact, the operation of the positioning device is difficult due to the tight snap fitting of the steel ball 303 into the slots.